Millions of documents are sent back and forth every day. Substantial effort and time is spent in the overhead of addressing these documents. In the workplace, this substantial time and effort results in increased cost and expense.
Many document management systems have been proposed and implemented in the past. These document management systems include systems that store documents and handle the coordination of requests with responses.
Machine readable codes have been applied to documents in the past as a way to manage the documents. In one such a case, bar codes are used as identifiers for document retrieval. Unfortunately, this technique is susceptible to a sort of “transfer attack” where the machine readable code is removed from one document and pasted onto another. See U.S. Pat. No. 5,754,308, issued to Lopresti et al.
Furthermore, a machine readable code must always include some form of identifier, which is normally a numeric value or bit sequence of sufficient length to identify a document uniquely among many such documents. Choosing an appropriate identifier is a complex matter, and many techniques have been developed over many years. However, these techniques assume that the document is either being created from an electronic original, or chosen randomly, or chosen according to some counting scheme or complex sequencing algorithm. This can be useful in many cases, but does not relate the contents of a paper document to the chosen identifier.